Crown bottle cap



Aug. 15, 1944.

' cnown BOTTLE CAP Filed Aug. 13, 1941 v Avvz/Wve, xPOEEPT/QJM/Th;

4 TMPNEVJ.

R. P. SMITH 2,356,012 r r This invention relates we bottle crow -er crown bottle ees as it'fis sometimes designated,

and "relates particularly to -fa novel structure which eIiminatesQthe use Offthe heretofore-emfployecl cork line-r" or composition c'ork lin'er' a'nd F which also permitsthe use'oi black-iron i-n pla'ce of the commonly hereto'fdre employed "tinned iron. s

, made :out of black iron insteadof having to :be tin coated. Tinisa1s0 one-of the -materials the supply" of which is seriously-affected in the present world crisis, particularly ior use-in non-de ffense articlesi ELL'A ,still further ti'on is to; provide a structure of the natureabove indicated'wherein the application of the crown 1101 11118 bottle resultsain a seal more perfect than ;has beenlobtained heretofore with the useof the rcork inserts Jncthis-regard, :it. has heretofore 1been 'a common practiceatol create the sealsbetween the crown and the bottle compressing the corkinsert directlyzagainst the, upperzendof .the bottle. ,Itso happensrthatrthe end partrof the bottle is thatpart which' issubject to shrink ageand change, inshapeasthe glass is formed andcooleddn the molding process. The present invention embodies a sealing between the crown and the outer circumferential part of the bead provided aroundthe' mouth of the 'bottle since this portion ofthe. head .is formed within the primary object o'f the inven 1i seri riwonioesai L 1 1; a N

while the c'rdwn 1 structure is changed and also the locationof the sealli is changed; =themnew structure-may be employed in" the-crowning machiner already" in use' witlr but the .minor change bfre-shapingthe end of the crown seatingplunger3 W 7;, .n Further-objects and advantages ofithe. invention will become apparent to those versed" in :the art in the following description of one particular form of the invention asillustrated in the accompanyingdr'awing, in which Fig. -1 is a top plan view of a crown embodying the inventiom on an enlarged scale;

r igi2, a bottom planiview of the crowm and mold and is quite uniform in contour anddi:

mensionsjallof which means'that a very im} portant advantage .is obtained by' the preset invention inthat the number of rejects"" d1s'- covered on test following the crowning 'operation are materiallyreducedand in" fact reduced tea-negli ible-quantityla V Anotherimr'i'ortarit'*object' of theinvention is to provide a crown :structur'e' of theabove indicated nature which may be'produc'edand applied at a' relatively low rcost," and in fact at a cost ultimately not exceedingthat of the heretofore work-lined crown. Another advantage is that "Fig; 3, a view in eentral'diametrical section through a crown as applied to a beverage. bottle, one, still further enlargedscale. H

"- Like characters of reference indicate. likeparts in "the several viewsinthedrawingh v s In the --forming of the crown;generally desig nated by the numeral'lmia sheet of metal, either tin "plate br=lolack iron, has applied *thereto in the flat state a sheet of treated. paper, generally designated by the numeral H theapaper being secured to the metal uniformly thereover by any suitable paper-to-metal adhesive, the exact composition of ithe :adhesive not entering into the presentinvention; Then in the usual man ner, the crowns In are punched or died-out from the sheettohavethe:paper H then forming'a liner on the inside of =the-crown as indicated in Figs. v2 and .3. In this :respect it is :tobe noted that the paperliner ltliollowsj iroundlthe inside of the crownato cover the entire interior face theretovand to terminate at the outer cut edge Aottheicrown. 5 p An important :change, appears in the; crown 10 .asacompared to the shape of the-crowns heretofore employed. Thischange consists in forming thedome B,-of the crownto have less radius of curvature than heretofore employed whereby the crown, curves ;outwardly accordingly. While the invention is not limited to this precise .dimension, in a crown designed to cap and seal the ordinary size of beverage bottle, this radius of curvature; of the dome -B.would be three inches whereas,- in comparison, the radius of. curvature employed heretoforewas five inches. L

The-flutes .I'2 between the ridges :around the side wall of the crown formingthecorrugations thereof: are; :limited :to extend to notmore than half wayclup the :side 'wallas measured from the undercut gedgieof;the crown.'1 r

i The paper liner Ll] .0fthe-crown is madegpreferalcily of woodrpulp but may-he :made of any which is combined with natural or synthetic res-.

ins, oils, waxes, or the like, to form a flexible and i P gpaper comes into intimate contact with the vapor-resistant coating over the paper in the neighborhood of a minimum of one millimter in thickness. The proportion of the rubber derivative in the coating compound may vary from five to which the crown is to be put (that is, the nature of the bottle contents), and the desired thickness of coating. The, rubber derivativeis roller coated on the paper commercially and is then dried. The coating may be allowed todry at room temperature but applicationof heat will reduce the drying period considerably. The minimum quantity of coating is approximately 2%:pounds to 2880 square feet of paper surface The. coating, of course, may be pigmented if de-;

sired; c

As above indicated, the paper liner H extends entirely around and down to the under cut edge of the crown and the paper may be sealed across its, edge with the-cut edge of the metal of the crown-by. any suitable material, such as one-of the; many available lacquers. This is particularly advantageous when the crown metal is .nottinned and is therefore subjectto'rusting. -The;. lacquer .seal will prevent entrance of moisture. orxliquids between ,the

- paper and the metal at this.line.'- Even though the metal of thecrown beFtinned-,-obviously the i cut edge will expose the base: iron leaving an 'untinned raw-edge, and again the sealwillgcoat overthis raw edge to prevent a rust line from appearing." 4

Now referring toFig. 3; a crown formed as above indicated is shown applied over the mouth of a glass bottle l3. The. shape of the bottle about themouth thereof is the usual shape employing the rounded bead l4. circumferentially around the bottle extending outwardly and downwardly from the top'end- Cofl the bottle, this-end C being substantiallvfiat over'a limited portion therearoundi As indicated in ..Fig. 3, the curvature of the: dome B of the crown I0 is such that the paper liner lliis heldabove this end zone C but is brought into intimate contact substantially over the entire area of the bead l4. When-the crown is placed on the bottle and the lower corrugated end is compressed in to grip under'the bead l4, the'paper liner II is thus pulled down and around the bead snugly and compressed thereagainst and thus maintained. r

In other'words the sealing area between the crown and the bottle I3 is that between the outer face of the bead I4 and'the inner face of the paper brought into contact therewith. As above indicated, this particular portion'of the bottle which forms this'bead face is subject to littleor no deformation as between any number of bottles molded so:that crowns held to precise dimensions will 'uniforr'nly effect a practically perfect seal withall bottles made in 'the same mold. .On the contrary, the upper end zone C with which crowns have heretofore been employed to effect a seal varyjust enough to cause a large number of sealed bottles to be rejected on account of leakage. Little variations are bound to occur in this end zone C due to lack of control in the manufacturing process of the bottles.

v V The seal between the'paper l l and the outer surface of the bead i4; is further enhanced by reason of the existence of the rubber'derivative coating on the surface of the paper II.

This rubber coating backed up with the resilient glass surface over the microscopic hills and hollows that may be present. The rubber dej rivative isa good adhesive when brought into to ninety-five per cent of the compound dependme upon the other materialsemployed, the; use

'such' intimate contact with the glass surface as is,occasioned during the crowning operation.

The beverage bottles being sealed will be sealed under thirty-two to forty pounds internal pressure. This pressure is exerted outwardly against the inner side of .th crown I0 tending to bulge it outwardly. This would mean that if there be any bulging of the dome B, the distance between the paper II and the bottle and C would tend to increase accordingly,particularly where the degree of curvatureof the domeB was slight or even approached the fiat state. The provision in the crown l0 in the present invention of r a dome B having a. greater curvature than usual anticipates this outwardly bulging tendency giving, in efiect a pre-bulged crown. Should there be any travel outwardly of the dome B, a tighter seal iseffected since the outward bowing of the dome B would tend to pinch inwardly the side wall of thecrown to effect a tighter seal against the bead l4. The seal would tend'to be broken .if it were maintained in the heretofore customary position across the zone C since the bulging. dome B; would tend to lift from that area. In other words gas pressure within the bottle tends to increase and main.- tain the seal formed-.: with the present inventio rather than reducing ,that seal.

Referring to Fig. 3 again, it is to be noted thatthe crown I!) must notonly seal against escape of liquid but alsogagainstv escape of gas which may arise from the top of the liquid or be present between the liquidand' the crown, Should there be a tendency for escape of gas even in a minute quantity, the gaswould have to travel between the paper II and over the end zone'C of the bottle into a gradually decreasing clearance space therebetween. During the inspection procedure, bottles are tested in one instance by turning them on end with the crown undermost and this, of course, brings the liquid against the paper II to'flow into this V-section cavity, thereby in itself tending'toform an ad'- ditional seal against travel of gas-from that cavity between the bead l4 and the paper I]. In other words the fact that the paper II is lifted and not in contact with the bottle'end zone C and forms therewith aIV-se'ction cavity circumferentially around the bottle, introduces a further sealing effect.

While the invention hasherein been shown and described in the one preciseforin, it is obvious do not. desire to be limited to. that; precise form beyond the limitations as may be imposed by the containers curved surface, said skirt being corrugated to permit crimping under said inwardly curved surface portion, and a resilient liner in said crown following the curvature of said major area and extending down said skirt at least far enough to engage said container outwardly curved portion, whereby said crown in its sealed condition on said container has said liner in sealing contact over said curved container surface, and substantially free of contact with said fiat surface to leave a V-section clearance between said liner and said fiat surface with the apex of said section substantially at the outer peripheral portion of the flat surface.

ROBERT P. SMITH. 

